Former DOE Fusion Chief, Robert Hirsch, says aneutronic fuel is path to fusion, and the tokamak will not provide practical energy
This update was part of LPP's November 2012 progress newsletter. Download a PDF of the full newsletter here.
“So where are we likely to find practical fusion power? First, we must look for a concept or concepts that are inherently small in size, which means high plasma density. Second, we must look for something that can be based on a low or zero neutron fusion reaction. One example is the proton-boron reaction.”
--So said Dr. Robert L. Hirsch, in a presentation given at the 14th U.S.-Japan IECF Workshop, October 16, 2012, and then widely reported in the New York Times blog, Dot Earth. In the same presentation, Dr. Hirsch concluded that the tokamak cannot lead to practical energy sources because it is too large, too expensive, and does not avoid radioactive waste due to neutron production.
Dr. Hirsch’s views are notable because, 40 years ago, he was director the Department of Energy’s fusion research program and was a key figure in pushing the program into its narrow emphasis on tokamaks, a major error that Dr. Hirsch now acknowledges. It is not news that Dr. Hirsch thinks tokamaks are a dead-end, as he has been saying something like this for about 15 years. But this is the most forceful statement he has made of these views, and the first to gain widespread media attention.
The only specific approach for aneutronic fusion that Dr. Hirsch cited in his speech was Inertial Electrostatic Confinement (IEC), which is understandable, since he was a pioneer of this approach before becoming an advocate of the tokamak, and the presentation was directed to an IEC workshop. (In response to various requests, LPP will soon release a comparison of the plasma focus with IEC and other approaches to aneutronic fusion.)
The attention given to Dr. Hirsch’s negative analysis of the tokamak came only a few weeks after a government report on the National Ignition Facility (NIF) revealed that it had essentially no chance of reaching fusion ignition (the self-heating of a plasma by fusion reactions) in the foreseeable future. NIF, based on a giant laser array, and the tokamak program have consumed (and still consume) the vast majority of US funding for fusion research. These two analyses show that it is long past due for the government to redirect its fusion funding in more inclusive directions.
Skepticism towards aneutronic fusion fuels has hindered LPP's ability to raise funds from governmental and other sources, since these funds are currently directed primarily towards the deuterium-tritium fusion approaches (especially tokamak) that are considered "easier" because of the lower ignition temperatures D-T requires. Fortunately, LPP published in March 2012 the achievement of ion energies sufficient for fusing the aneutronic fuel combination hydrogen and boron, and we hope this technical progress along with new statements like this one from Dr. Hirsch will continue to increase the odds for a more diverse fusion program with a greater likelihood of both scientific and commercial success.
Below: Artist’s concept of a polywell IEC generator by Torulf Greek, who is also responsible for LPP’s Focus Fusion depictions. Join conversations about the polywell and other fusion approaches at talk-polywell.org, focusfusion.org, and fusionenergyleague.org.